diff --git a/video-konverter/app/static/tv/css/tv.css b/video-konverter/app/static/tv/css/tv.css
index 0b94c1c..83ff31f 100644
--- a/video-konverter/app/static/tv/css/tv.css
+++ b/video-konverter/app/static/tv/css/tv.css
@@ -1814,6 +1814,31 @@ textarea.input-editing {
     font-size: 0.75rem;
 }
 
+/* Serie als gesehen markieren - Button */
+.tv-mark-series-btn {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.4rem;
+    padding: 0.5rem 1rem;
+    background: transparent;
+    border: 1px solid var(--border);
+    color: var(--text);
+    border-radius: var(--radius);
+    cursor: pointer;
+    font-size: 0.9rem;
+    transition: background 0.2s, border-color 0.2s;
+}
+.tv-mark-series-btn:hover,
+.tv-mark-series-btn:focus {
+    background: var(--bg-hover);
+    border-color: var(--accent);
+}
+.tv-mark-series-btn.active {
+    background: var(--accent);
+    color: #000;
+    border-color: var(--accent);
+}
+
 /* --- Episode Card-Grid (Phase 5, Plex-Style) --- */
 .tv-episode-grid {
     display: grid;
diff --git a/video-konverter/app/templates/tv/series_detail.html b/video-konverter/app/templates/tv/series_detail.html
index a10711c..6236be9 100644
--- a/video-konverter/app/templates/tv/series_detail.html
+++ b/video-konverter/app/templates/tv/series_detail.html
@@ -63,6 +63,15 @@
                     <span class="watchlist-icon">{% if in_watchlist %}&#9829;{% else %}&#9825;{% endif %}</span>
                     <span class="watchlist-text">{{ t('series.watchlist') }}</span>
                 </button>
+                <!-- Serie als gesehen markieren -->
+                <button class="tv-mark-series-btn"
+                        id="btn-mark-series"
+                        data-focusable
+                        data-series-id="{{ series.id }}"
+                        onclick="markSeriesWatched(this)">
+                    <span class="mark-series-icon">&#10003;</span>
+                    <span class="mark-series-text">{{ t('status.mark_series') }}</span>
+                </button>
             </div>
         </div>
     </div>
@@ -254,6 +263,54 @@ function toggleWatched(videoId, btn) {
     .catch(() => {});
 }
 
+function markSeriesWatched(btn) {
+    // Alle ungesehenen Episoden aus ALLEN Staffeln sammeln
+    const allCards = document.querySelectorAll('.tv-episode-tile:not(.tv-ep-seen)');
+    const ids = [];
+    allCards.forEach(function(card) {
+        var vid = card.dataset.videoId;
+        if (vid) ids.push(parseInt(vid));
+    });
+    if (ids.length === 0) return;
+
+    // Batch-Request an API (gleiche Methode wie markSeasonWatched)
+    Promise.all(ids.map(function(id) {
+        return fetch('/tv/api/watch-progress', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ video_id: id, position_sec: 100, duration_sec: 100 }),
+        });
+    })).then(function() {
+        // Alle Episoden-Cards als gesehen markieren
+        document.querySelectorAll('.tv-episode-tile').forEach(function(card) {
+            card.classList.add('tv-ep-seen');
+            var markBtn = card.querySelector('.tv-ep-tile-mark');
+            if (markBtn) markBtn.classList.add('active');
+            var thumb = card.querySelector('.tv-ep-thumb');
+            if (thumb && !thumb.querySelector('.tv-ep-watched')) {
+                var check = document.createElement('div');
+                check.className = 'tv-ep-watched';
+                check.innerHTML = '&#10003;';
+                thumb.appendChild(check);
+            }
+        });
+        // Alle Staffel-Tabs als komplett markieren
+        document.querySelectorAll('.tv-tab').forEach(function(tab) {
+            if (!tab.classList.contains('tv-tab-complete')) {
+                tab.classList.add('tv-tab-complete');
+                if (!tab.querySelector('.tv-tab-check')) {
+                    var check = document.createElement('span');
+                    check.className = 'tv-tab-check';
+                    check.innerHTML = ' &#10003;';
+                    tab.appendChild(check);
+                }
+            }
+        });
+        // Button-Zustand aendern
+        btn.classList.add('active');
+    }).catch(function() {});
+}
+
 function markSeasonWatched(seriesId, seasonNum) {
     const season = document.getElementById('season-' + seasonNum);
     if (!season) return;